The principle of least action

The principle of least action (Fermat, Maupertuis, Euler,…) confirmed by analytical mechanics (Lagrange, Hamilton-Jacobi,…) is based on the following proposal: nature does not like too tiring.

This physics ignores friction. She won’t know the disorder, entropy. It is therefore powerless to dissipe kinetic energy.

The principle of worst action

For a valve, thermodynamics principles will be used in the form: energy is conserved but energy must be degraded, thus showing our determination to create a lot of irreversibilities, entropy, disorder. The second law of thermodynamics will be high here to the principle of worst action, which frontally opposes the principle of least action, from which its name.

Massive and rapid kinetic energy degradation is a little-known area of thermodynamics.

In the physics book, here presented, it is shown in particular how it is possible to put a deep disorder in the molecular world to escape chaos in our macroscopic world.